The present invention relates generally to a patient monitor. More particularly, the present invention relates to a system, method and software program product for analyzing video frames of a patient and determining from motion within the frame if the patient is at risk of a fall.
Fall reduction has become a major focus of all healthcare facilities, including those catering to permanent residents. Healthcare facilities invest a huge amount of their resources in falls management programs and assessing the risk of falls in a particular patient class, location, and care state, along with the risk factors associated with significant injuries. Recent studies have found fall rates at 2.2 to 7.0 (per 1000 patient bed days) in acute care hospitals, 11.0 to 24.9 in long-term care hospitals, and 8.0 to 19.8 in rehabilitation hospitals, with the majority of falls occurring from, or near, the patient's bed, usually by patients who should not ambulate without assistance. The patient's mental status is most often listed as the most common risk factor contributing to falls. Bed falls can account for up to half of all falls in a healthcare facility. The range of injury from all falls has been reported to be at a rate of 29 to 48 percent, with 4 percent to 7.5 percent resulting in serious injury to the patient. The intention of these studies is to improve patient care by providing adequate monitoring programs corresponding to the perceived patient risk and injury. Realistically, however, it is simply impossible to know for sure which patient will fall, and the severity of the injury that may result from any fall. Bed falls have received an extensive amount of scrutiny due to the patient's high expectation of safety and the disproportional potential for severe injury to the patient over other types of falls.
Round the clock patient monitoring by a staff nurse is expensive, therefore, healthcare facilities have investigated alternatives in order to reduce the monitoring staff, while increasing patient safety. In the past, patients at risk of falling from their beds were either physically restrained or sedated, regardless of the patient's mental status. Both of these preventives are now considered to be measures of last resort that are reserved for unruly or incompetent patients. Presently, falls prevention is subdivided into intervention and monitoring techniques. Interventions are aimed at minimizing falls risk and include such measures as ensuring that the patient can reach necessary items from the bed, ensuring that the bed is in a low position and the bed brakes are locked, ensuring that the patient has a manual bed call button within reach for summoning a nurse and that a charge nurse responds (albeit verbally) to every call. Other interventions include the use of half length bedrails to reduce the patient's need to climb over rails to exit the bed and keeping the bedside area uncluttered and obstacle free. Perhaps the most easily implemented intervention is clear instructions from an attending nurse to request assistance prior to leaving the bed.
Healthcare facilities rely on patient monitoring to supplement interventions and reduce the instances of patient falls. Eyes-on monitoring of patients is problematic for two reasons, cost and privacy. Most facilities maximize the patient-to-nurse staffing ratios by care units, e.g., recovery and critical care units have a lower patient-to-nurse staffing ratio than floor bed units, and, typically, bed patients demand greater privacy than those in critical or special care units. For these reasons, patient monitoring has relied on technological solutions rather than nurse monitoring. Note however, that these solutions are alerting devices, used as an aid for patient care and are not a substitute for adequate quality staffing.
Prior art fall prevention monitors include alarms using pressure sensitive pads or position sensitive transmission patches. The first type of fall prevention monitor uses a pressure sensitive pad that senses the patient's body mass. If the sensor detects a change in the patient's body mass, a remotely located alarm is sounded to summon staff. These monitors are extremely adaptable and may be placed in one or more locations on the patient's bed, on the floor adjacent to the bed, on chairs, toilet seats, wheel chairs and almost any other place that a patient may rest. These devices have gained considerable acceptance in the healthcare industry because they are relatively inexpensive, non-intrusive, exhibit a fairly low instance of false alarms and are reliable. These monitors can be used in tandem to more accurately assess the position of a patient, thereby further reducing false alarms. For instance, the system may be configured with one pressure sensitive pad in the bed and under the patient and a second pressure sensitive pad on the floor. Then, the staff will be alerted whenever a patient's weights shifts off of the bed pad and again when the patient's weight is sensed by the floor pad.
Detractors to pressure sensitive fall prevention monitors counter that these types of devices may be more accurately described as “patient fall detectors” than “fall prevention monitors” because they typically alert only after a fall has occurred and the patient's weight has shifted out of the bed. In other words, prior art pressure sensitive fall monitors cannot perceive that the patient is in the process of getting out of bed, only that the patient's weight has left the bed. Additionally, poorly placed pressure sensitive pads may send multiple nuisance alarms that must be responded to and then to reposition the pressure sensitive pad requires that the bed be empty.
More recently, patient position sensitive transmission patches have been introduced that sense the position of a body part and send an alarm if the part is in a “near weight bearing position.” The “patch” is a battery powered inclinometer, processing circuitry and a transmitter enclosed in an adhesive patch that is used in conjunction with a wireless receiver and alarm. The patch may be applied to the back of a patient's thigh parallel with the femur. Whenever the patient's thigh is approaching a weight bearing angle, the patch sends an alert signal to the remote receiver and an alarm sounds. These position sensitive transmission patches are relatively inexpensive and can be worn continuously for up to three weeks. The downside is battery life. The transmission patch device is essentially in a sleep mode when the patch is horizontal and consumes relatively little power, however when the patch is oriented off horizontal, the inclinometer and associate electronics are continuously processing measurements. Alert transmissions consume even more battery power.